About This Calculator

The expected date of delivery (EDD) and estimated conception date computed by this calculator are for informational purposes only and by no means shall be used as the exact dates for these events. For more accurate dates, please consult a doctor or your personal physician.

Please note: only about 5% of babies are born on their actual due dates.

While mothers typically carry their unborn babies in the uterus for around 38 weeks, the 40-week "weeks pregnant" count begins on the first day day of the woman's last period, not on the date of conception which is about two weeks later.

Pregnancy FAQs

How do you calculate your estimated delivery date?

Are you wondering "when am I due"? The basic formula to calculate it is very simple and works great if your average cycle length is 28 days. Simply add 280 days (or 40 weeks) to the first day of your last period. If you know when conception happened then just add 266 days (or 38 weeks).

However, things can get complicated if your cycle length is not 28 days or if your luteal phase length is not 14 days. The above tool makes it easy to adjust for these sorts of shift by letting you specify your information.

What is LMP?

LMP stands for Last Menstrual Period. First day of LMP can be used to calculate a baby's EDD.

What is average cycle length?

Cycle length is the length of a woman's menstrual cycle. Most women's average is 28 days.

What is luteal phase?

Luteal phase is the part of the cycle that starts at ovulation and ends the day before your next period. The average length of luteal phase in women is 14 days and does not usually vary by more than a day from person to person.

Delivery Facts

Only about 5% babies are born on their actual EDD.

Ultrasound can predict your date more accurately in early stages of pregnancy. It is useful if you did not keep track of your periods or do not remember the date of your last menstrual period.

80% of babies are born within 10 days of the predicted day.

20% of babies are born outside the normal 10-day window. Babies born more than 10 days before are pre-mature. Babies born more than 10 days after are post-mature.

There is something miraculous about a woman's reproductive system. Despite the pain and discomfort that menstruation can cause for many women, it signifies the ability to produce a new life. However, despite the proliferation of television shows about unwanted pregnancies, planning requires knowledge of your cycle, including knowing when you will ovulate.

Having this information increases your chances if you want a child. Additionally, knowing your cycle helps you avoid pregnancy when the timing isn't right.

Ovulation

For many women, there comes a time when she decides that she is ready to have a baby. Most couples in their 20s to early 30s who are having regular, unprotected sex have approximately a 20 percent chance of conceiving each cycle, and 85 percent of these couples will conceive within a year. As previously mentioned, however, having a baby isn’t always as simple as just having regular unprotected intercourse, especially if you do not have intercourse regularly or if you are in your mid 30s or older. Knowing your probable ovulation times, as well as how to tell if you are ovulating, can improve your chances of conceiving.

A woman is born with all of the eggs she will ever release in her lifetime. On average, one egg matures and is released each month. When more than one egg is released and they are both fertilized, a woman will give birth to fraternal twins if both embryos develop. Fraternal twins are twins that are not identical but are born at the same time.

Ovulation occurs when the luteinizing hormone ripens an egg and causes it to be released into the fallopian tube. The egg travels down the tube, where it can be fertilized by sperm. If the egg becomes fertilized, the embryo burrows into the blood-rich lining of the uterus between six and 12 days after the egg is fertilized. If the embryo and the woman are healthy, the embryo will develop into a baby. If the egg is not fertilized by sperm, it is absorbed into the uterine lining during menstruation.

The egg cell, or ovum, can live for 12 to 24 hours in the fallopian tube before it is no longer viable. Sperm can live for up to seven days, but they typically only live for three to four days. How long the sperm live depends on several factors. First, the closer the sperm are to the cervix, the better chance they have of making it to the fallopian tube and surviving long enough to fertilize the egg. Sperm deposited near the cervix have less distance to swim to reach the fallopian tube, and they are exposed to the acidic environment of the vagina for less time. In addition, if the woman is close to the time of her ovulation, the cervical mucus changes. The mucus becomes thinner, which helps the sperm pass through the cervix and swim up to the fallopian tubes.

Sperm can live outside of the body for 20 minutes to one hour, depending on where the sperm was deposited. This is why the withdrawal method of birth control is not necessarily effective. First, before a man ejaculates, he deposits pre-ejaculate, and this fluid may contain sperm. Second, if the man ejaculates near the vaginal opening, there is a small chance that the sperm will survive and enter the vaginal opening, which can cause pregnancy.

Ovulation can occur even before a girl begins to menstruate, or after a period of not menstruating, such as when the woman is breastfeeding or when she is going through menopause. As a result, it is important to always use birth control when you have sexual intercourse if you wish to avoid pregnancy, because you might still become pregnant even without a menstruation.

Signs of Ovulation

When a woman ovulates, her body goes through many changes. The first sign is a change in the cervical mucous. Every woman's cervical mucous is different. As a result, it is important to know what your cervical mucous looks and feels like so that you will be able to identify the changes that indicate that you are ovulating. During ovulation, the mucous becomes less cloudy and stretches when it is placed between the fingers and the fingers are drawn slowly apart. Many woman may also have more cervical mucous when they are ovulating.

In addition to the changes in the cervical mucous, the cervix itself may also change. During ovulation, the cervix may feel softer, as well as higher, more open, and/or moister, according to the APA. To determine if your cervix has changed, you should become familiar with how our cervix feels normally. Feel your cervix each day over the course of a month, and you should begin to notice the changes in the cervix when you ovulate.

Perhaps the most sure sign of ovulation is a change in the basal body temperature. The basal body temperature is the lowest average temperature in a 24 hour period. When a woman ovulates, her basal body temperature will increase 0.4 to 1.0 degrees Fahrenheit, as measured by a basal body temperature thermometer.

Basal body temperature thermometers are oral thermometers that measure very slight variations in degrees. Regular thermometers are not sensitive enough to detect the slight change in temperature that can indicate pregnancy. To use a basal body temperature thermometer, insert it into your mouth the first thing in the morning, before you get out of bed. This is the best time to take your temperature because you haven't started moving around or put on heavy layers of clothing. These can influence your body temperature and give you a false reading. Use your basal body thermometer each day and record the temperature. When you notice a slight rise in temperature, you may be ovulating. However, you are most fertile in the two to three days before ovulation because it may take the sperm that long to travel through the uterus to the Fallopian tubes.

Some women also feel a slight twinge or cramping when they ovulate. This pain is called mittelschmerz, which means "middle pain" in German. This light cramping may last a few minutes up until a few hours. Some women also notice a light amount of spotting. However, most women do not experience pain or spotting during ovulation.

Tracking Ovulation

Tracking your ovulation is important, whether you are trying to become pregnant or avoid it. In addition to paying attention to the physical signs of ovulation, such as your cervix, cervical mucous, and basal body temperature, you can track the probable dates by keeping track of your cycle. Most women ovulate between the 10th and 20th day of their cycle, provided they have a 28 day cycle.

To track your ovulation accurately, you should keep track of your cycle each month.. Then, over the course of a few months, record your basal body temperature. Over time, you will begin to notice a pattern in the date on which your temperature spikes. For example, you may notice that your basal body temperature spikes on the 15th day of your cycle. This means that to maximize your chances of conceiving, you should have intercourse on the 12th and 13th day of your cycle. Alternatively, if you are trying to avoid conception, you should refrain from intercourse the week before your basal body temperature spikes until a day after it spikes.

Many women use commercial ovulation predictor kits, or OPKs, in addition to tracking with their cycle, cervical changes, and basal body temperature. These kits can predict ovulation up to a day in advance. Commercial predictor kits work in a similar way as pregnancy tests in that you urinate on the test strip or dip the test strip into a small cup of urine. These tests typically work by measuring the levels of follicle stimulating hormone, of FSH. If you are ovulating, the strip will change in the manner indicated by the instructions on the test. Unlike pregnancy tests, however, ovulation tests typically come with seven to 10 strips per package. You should begin using them ten days after the start of your last period, or as directed by the package instructions.

By using several methods of tracking, you will improve your chances of becoming pregnant significantly, provided that you are in good health. Predicting ovulation allows you to plan in a way that having unprotected sex without tracking does not. For example, if you are a teacher and you wish to have a baby during your summer vacation, tracking your schedule improves your chances of having a baby during summer.

Menstruation

Menstruation is the normal, monthly process by which the uterus sheds its lining. This lining is known as the endometrium. When a woman does not become pregnant, her body begins the process of discarding the unneeded endometrium through the vagina. Shedding the endometrium in this way allows the growth of a new lining, which will support a baby if she becomes pregnant.

The hormones from the pituitary gland and the hypothalamus in the brain control ovulation and menstruation. Specifically, estrogen and progesterone control menstruation. Estrogen causes the lining of the uterus to build up, and progesterone helps keep the lining in place for a few days after ovulation. Then, the amounts of progesterone and estrogen decrease, which causes the uterus to begin to shed its lining. When the first drops of blood exit through the vagina, a woman’s period begins.

The Normal Menstrual Cycle

Girls begin menstruating between the ages of 11 and 14, according to the the Mayo Clinic website some of these conditions include:

Endometriosis. Endometriosis is a condition in which the uterine lining grows outside of the uterus, such as in the fallopian tubes or even in the pelvis. Women with endometriosis may experience painful menstruation because the lining is shed into the pelvic cavity or somewhere else where it can’t escape, which causes pain and inflammation.

Adenomyosis. When a woman suffers from adenomyosis, the lining of the uterus grows within the muscles lining the uterine wall. Like endometriosis, the lining is shed but the body has difficulty expelling it.

Fibroid cysts. Fibroid cysts are benign cysts that grow along the uterine walls. These cysts do not typically cause pain, but some women with fibroids experience more painful than normal menstruation.

Pelvic inflammatory disease, or PID. PID is caused by a sexually transmitted bacterial infection. PID causes pain in the lower abdomen even when the woman is not menstruating, but thispain can intensify when she is menstruating.

Cervical stenosis. Cervical stenosis is caused by a cervix that is abnormally small, making it difficult for blood to pass through. This causes painful menstruation because the lining creates intense pressure on the cervix as it tries to pass through.

The most effective way to alleviate m pain is to eliminate or treat the underlying cause, if applicable. If your physician suspects that your pain is caused by a medical condition, she may order tests to determine the cause of the problem. These tests will reveal problems that are visible, such as endometriosis. These tests may include:

Ultrasound. During an ultrasound, the physician or technician uses high-frequency sound waves to make an image of soft tissues.

Computerized tomography, or CT scans. A CT scan uses a combination of x-rays and computer imaging to make a more detailed image of the organs and tissues.

Magnetic resonance imaging, or MRI. An MRI uses the body’s natural magnetism to create an image.

Hysteroscopy. During a hysteroscopy procedure, the physician inserts a thin tube with a light and camera at the end to look inside the vagina, cervix, and uterus. Hysteroscopy is most often used to check for fibroid cysts or cervical stenosis.

Laproscopy. During laproscopy, the physician inserts a tube with a light and camera at the end through a small incision made in the abdomen. Laproscopy is particularly effective at revealing endometriosis.

If the test or tests that your physician orders reveals a medical problem, they can usually treat the problem with medication or surgery. In many cases, resolving or treating the problem will also ease the pain from the cramps.

In many cases, however, the cramps are not caused by a medical problem. If the pain is not caused by an underlying medical condition, there are a few ways to relieve the pain from cramps, including:

Non-steroidal anti-inflammatory drugs, or NSAIDs. NSAIDs include ibuprofen, such as Advil or Motrin, or naproxen, which is also known as Aleve. The physician may choose to recommend a prescription-strength NSAID such as mefenamic acid, also known as Ponstel.

Birth control. Birth control pills, as well as shots, patches or other devices that contain hormones, often help relieve painful cramping. These hormonal birth control methods also regulate an irregular cycle. The hormones in these pills not only prevent the ovulation, they also reduce the effect of the prostaglandins.

Applying heat. Heating pads and hot baths often reduce the inflammation and pain caused by menstruation.

Exercise. Exercise can reduce cramps by warming up the muscles and causing the release of endorphins, or chemicals in the brain that ease pain and cause pleasurable feelings.

Nutritional supplements. Some supplements, such as vitamin B6, vitamin B1, magnesium, omega-3 fatty acids, and vitamin E, may reduce the pain from cramping.

Acupuncture. Some studies suggest that acupuncture may reduce the pain from cramps.

Transcutaneous electrical nerve stimulation, or TENS. TENS raises the pain threshold and helps release endorphins. A special machine is necessary to apply TENS. This machine delivers a low level of electrical current.

Some of these methods work for some women, but not for others. However, there is no reason to live with painful cramps. Finding an effective remedy can take time and experimentation, but most women find a method that works for them.

In addition to cramps, some women experience other symptoms during menstruation. These symptoms include bloating, fatigue, difficulty concentrating, and mood swings. According to the Steady Health website, up to 85% of women report one or more of these symptoms.

Feeling bloated or moody up to a week before your period is normal, as long as it does not interfere with your daily life. However, if you feel as if your symptoms are so severe that your ability to function during your day to day activities is affected, then you may be experiencing PMS or PMDD. PMS and PMDD tend to be at their worst in the late 20s and early 30s. Then, over time, the symptoms tend to improve as menopause approaches and hormone levels begin to naturally decrease, according to the Mayo Clinic website.

There are two types of PMS. The first kind is characterized by irritability, mood swings, anxiety, or depression. Researchers believe that this kind of PMS is caused by an imbalance between the levels of estrogen and progesterone. When there is too much estrogen, feelings of anxiety often result. Conversely, if there is too much estrogen, women may feel depressed. The second type of PMS causes sugar cravings, headaches, and fatigue. This type of PMS may be caused by hormones which increases sensitivity to insulin.

If the symptoms are so severe that they lead to thoughts of suicide or severely impact the woman’s ability to lead her life, she may have premenstrual dysphoric disorder, or PMDD. The symptoms of PMDD are very similar to PMS, except they are more severe. According to the PubMed Health website, three to eight percent of women experience PMDD during their reproductive years.

No matter which type of PMS you have, or if you have PMDD, you can seek help if the symptoms become overwhelming. Physicians suggest a variety of treatment options, depending on the type and severity of the symptoms. Some treatment options include:

Antidepressants, particularly selective serotonin reuptake inhibitors, or SSRIs, may decrease the depression, food cravings, and fatigue that a woman feels before or during her period. SSRIs include fluoxetine, known by the brand name Prozac; paroxetine, known as Paxil or Pexeva; or sertraline, which is known by the brand name Zoloft.

NSAIDs like ibuprofen can relieve cramps and breast tenderness if they are taken before the symptoms begin.

Diuretics can reduce the water weight gain and bloating that many women experience.

Hormonal birth control can ease mood swings and reduce man of the symptoms of PMS.

Watching your diet, including the amount of salt, sugar, and carbohydrates you eat before your period can reduce feelings of fatigue as well as water weight gain.

Avoid caffeine and alcohol, which can affect the moods as well as increase cramping.

Exercising can increase positive feelings and reduce cramping and water weight gain.

Get enough sleep. Being well rested can improve the mood swings as well as reduce feelings of fatigue.

Take a multivitamin. Vitamins such as vitamin B6, vitamin E, magnesium, and calcium can reduce fluid retention, reduce cramping and breast tenderness, and improve mood.

While experiencing some symptoms during the week immediately before your period begins is normal , you don’t have to live with symptoms that cause you extreme discomfort. If your PMS or PMDD symptoms cause you to have problems with your everyday life, consult your physician.

Tracking Your Menstrual Cycle

It is important to keep track of your cycle because each time you visit a physician, she will ask you the first day of your last period. Your physician asks this to not only make sure that you are not pregnant, but also to make sure that you are not experiencing problems with your health. If you are younger than 40, missing or irregular periods might indicate that you have a health problem, such as poor nutrition.

If you have regular periods and suddenly your period is a week late, for example, you should take a pregnancy test. In addition, if you decide to try to become pregnant, knowing your cycle can help you determine the best days to have intercourse to conceive. Alternatively, knowing your cycle can also help you avoid pregnancy because you can avoid having intercourse of the days where you are probably the most fertile.

To calculate the length of your cycle, begin with the first day you begin spotting or bleeding. This counts as day 1. Then, track the days until the next one begins. The time from the first day you begin spotting or bleeding to the last day before you begin spotting or bleeding again is your cycle.

Factors Affecting Your Cycle

A number of factors can affect the length and regularity of your cycle. Pregnancy halts the cycle for most women, although some continue to spot or even bleed lightly for the first few months of pregnancy. Any bleeding during pregnancy should be evaluated by a physician, however, to ensure that there is no cause for concern.

Another factor that can affect menstruation is weight. Overweight and obese women are more likely to experience irregular periods. This is because the fat cells trigger the production of additional estrogen, which serves to keep the lining of the uterus thick. As a result, overweight and obese women may have longer cycles, or may just experience irregular cycles as the hormone levels fluctuate.

Conversely, low weight can cause periods to cease or become irregular as well. The low amount of body fat may cause insufficient amounts of estrogen, which can cause periods to cease or become irregular. Alternatively, if the woman is very thin because of lack of food or poor nutrition, the cycle may also stop.

Taking certain medications can also affect your cycle. For example, birth control pills regulate the length and timing of your period by artificially introducing hormones into your system that affect menstruation. However, other medications, especially medications containing hormones, can also have an effect on menstruation.

Stress and emotions can also play a role in menstruation. When a woman is very stressed, her periods may stop or become irregular. When you experience a lot of stress and negative emotions, your body produces extra amounts of a hormone called “cortisol.” Cortisol can affect the other hormones associated with menstruation, throwing off your regular cycle.

Breastfeeding or a recent pregnancy or miscarriage can also affect the menstrual cycle. After pregnancy or a miscarriage, the body may need a month or more to adjust. During this time, the hormone levels begin to stabilize and when they reach normal levels, your periods will become regular again. Breastfeeding can also temporarily halt menstruation or throw off your normal cycle. This condition is known as “Lactation amenorrhea,” according to the Kellymom website.

Problems with Fertility

Ten percent of couples in the United States experience problems with conceiving a baby. Infertility is defined as being unable to conceive despite having regular, unprotected sex for a year. Infertility can be caused by a variety of issues. These problems include:

Endometriosis. As previously mentioned, endometriosis is a condition in which the lining of the uterus grows outside of the uterus. When suffering from endometriosis, you can use of fertility drugs, artificial insemination, or surgery to remove the abnormal or problematic tissue.

Ovulation problems. Some women do not ovulate regularly, particularly as they get older and approach menopause. Women over the age of 35 may not ovulate with each cycle, and it may become more erratic and less frequent as menopause approaches. Some solutions to this problem include the use of fertility drugs and/or in vitro fertilization, or IVF. In vitro fertilization involves harvesting the eggs and fertilizing them in a laboratory, then implanting them in the uterus.

Blocked Fallopian tube. When the Fallopian tubes are blocked, either because of a structural problem or a surgery, the sperm is unable to reach the egg. IVF may help in this instance.

Poor egg quality. Over time, the egg quality decreases with aging. In this instance, IVF may be attempted with a donor egg.

Polycystic ovarian syndrome, or PCOS. PCOS is a condition in which the eggs do not ripen and release correctly. Solutions to this problem include medications to induce ovulation, fertility drugs, changes in diet, and weight loss.

Sperm allergy. In a small number of cases, a woman may be allergic to sperm. In these cases, in vitro fertilization may allow conception because it introduces the fertilized egg into the uterus rather than the sperm.

If you have been tracking your cycle, and have unprotected sex regularly, you should conceive within a year. If you have not conceived within this time frame, you may be experiencing a fertility problem. Your physician may be able to help in many instances. Make an appointment with your gynecologist for an examination. The sooner you are examined, the sooner you may be able to conceive.

Menopause

A woman’s cycle begins to become less regular as she ages. After the age of 40, many women begin to produce less estrogen and progesterone, and the periods become less frequent or become irregular. They may also become heavier or lighter than she experienced in previous years. Menopause is defined as the cessation of periods for one full calendar year, according to the PubMed Health website. Most women experience menopause between the ages of 45 and 55.

Some women may experience menopause earlier than 45, or later than 55. The age at which menopause is reached is largely dependent on family history. For example, if your mother experienced menopause at age 60, you will probably experience menopause around that age as well. However, your hormone levels and general health also play a role in the age at which you experience menopause. Women who have had a hysterectomy or a condition that affects the hormones may experience menopause earlier or later than she might normally.

The symptoms of menopause vary. Some women experience few symptoms, and except for the cessation of menstruation, they might not be aware of their hormonal changes. Other women experience a variety of symptoms for years before her period finally ceases. These symptoms may include:

Heart pounding or palpitations

Flushing or red skin

Hot flashes

Night sweats

Difficult sleeping

A decrease in sexual desire

Headaches

Problems with memory

Vaginal dryness

Incontinence or light urine leakage

Joint pain

Increased number of vaginal infections

If you believe that you may be experiencing symptoms of menopause, visit your gynecologist or family physician. This is particularly important if your symptoms are interfering with your everyday life, such as if insomnia is causing you to be too tired during the day to function effectively. Your physician can perform tests to determine if you are going through, or have already experienced, menopause. According to the PubMed Health website, hese tests include:

Eastradiol test. An estradiol test measures the levels of estradiol, or the form of estrogen that affects menstruation and fertility. To conduct an estradiol test, your physician or a lab technician will take a sample of blood.

FSH, or follicle stimulating hormone, test. The FSH test measures that amount of follicle stimulating hormone, which is secreted by the pituitary gland. It causes the follicles in the ovaries to become stimulated and release an egg. Levels fluctuate naturally each month. When the level reaches its peak, the egg is released. However, low levels may indicate that the woman is going through menopause. This test is conducted through a blood sample. Your physician may ask you to come in during a certain day of your cycle for this test to control for the natural fluctuations of this hormone in your body over the course of the cycle.

LH, or luteinizing hormone, test. The LH test measures the amount of luteinizing hormone in the blood, which controls ovulation. Like the FSH test, your physician will draw a sample of blood during a certain time in your cycle to determine the amount of luteinizing in your blood.

If menopause is bearable and relatively free from troublesome symptoms, your physician may not prescribe any medications. However, women who are experiencing problems with their symptoms may require hormone therapy to replace part of the lost hormones, and therefore ease the transition and lessen the effects of the loss.